| 摘要 |
PURPOSE:To obtain non-contact type switching operation, wherein if a magnet approaches a superconductor, the superconductor comes into a normally conductive state so that a switch turns ON, while if the magnet separates far from the superconductor, the switch turns OFF, by providing the superconductor and the magnet capable of approaching the superconductor. CONSTITUTION:A switch device can perform ON-OFF operation without bringing a permanent magnet 12 and a superconductor 30 into contact with each other, so as to prevent imperfect contact or the like caused by abrasion. Current flows from a power supply 34 to the superconductor 30 inside a cooling container 20 via a conductor 32. In non-operation of key, liquid nitrogen 28 supplied from a cooler 26 cools the superconductor 30 so as to keep it in a superconductive state, and thereby, a resistance change detector 36 outputs an OFF signal. Meanwhile, the pushing-down of a key top 10 makes the permanent magnet 12 approach the superconductor 30 so that the superconductor 30 transits to a normally conductive state beyond a critical magnetic field, and thereat, the resistance change detector 36 outputs an ON signal. In addition, the pushing-down of the key top 10 is stopped so that the key top 10 returns to the former position, and thereat, the resistance change detector 36 outputs the OFF signal. |
